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OK, I am having a problem. I come from CFD where we do not use "midside nodes". I am currently in a structural position where we use ANSYS for everything. I typically use the 'eyeball' test to see whether or not my mesh needs refining. I assume that it does not need to be quite as fine as a CFD run. With that said, our structures lead insists on using midside nodes, even though any time I try to use them, I get erroneous answers. I've read through the ANSYS help, which compares linear (no mids) and quadratic (mids) elements. It basically just says that it you are using linear elements, make sure the grid is "decent" in areas of high gradients (makes sense). It also even says that for nonlinear structural analses, one typically obtains better accuracy at less expense if you use a fine mesh of linear elements rather than a coarse mesh of quadratic elements.
It goes on even to say that for non-structural analyses, the linear elements are as good as the higher-order elements, and are less expensive to use. Even degenerate elements produce accurate results for these analyses. The current problem I'm doing involves calculating equivalent housing spring rates...easy. I'm applying a small load on a housing and looking for deflections. It seems to me that using linear elements is perfectly fine. More importantly, I'm getting good results.
I guess the question is: what are your thoughts on using midside nodes? When have they hurt/helped? Anytime I've personally tried to use them, they have failed and failed miserably.
Also, what exactly is being solved at the midside nodes? It can't be the entire governing equations, otherwise they would simply be additional nodes/elements. It must be some simple intraelemental equation that's being solved, but I can't find information anywhere. I really want some good background on these things so I can determine if they are worth my time.
thanks a lot,
It goes on even to say that for non-structural analyses, the linear elements are as good as the higher-order elements, and are less expensive to use. Even degenerate elements produce accurate results for these analyses. The current problem I'm doing involves calculating equivalent housing spring rates...easy. I'm applying a small load on a housing and looking for deflections. It seems to me that using linear elements is perfectly fine. More importantly, I'm getting good results.
I guess the question is: what are your thoughts on using midside nodes? When have they hurt/helped? Anytime I've personally tried to use them, they have failed and failed miserably.
Also, what exactly is being solved at the midside nodes? It can't be the entire governing equations, otherwise they would simply be additional nodes/elements. It must be some simple intraelemental equation that's being solved, but I can't find information anywhere. I really want some good background on these things so I can determine if they are worth my time.
thanks a lot,